The present invention relates to automatic chemical testing apparatus and more particularly to improved means for sample handling therein.
The present invention comprehends an improvement in the type of automatic chemical testing apparatus disclosed in commonly assigned U.S. Pat. No. 3,622,279 issued Nov. 23, 1971 to John J. Moran, the disclosure of which is incorporated herein by reference. The disclosures of commonly assigned U.S. Pat. Nos. 3,672,477; 3,716,338; 3,723,066; 3,728,079; 3,728,080; and 3,762,879 all relating to the same type of apparatus are also incorporated herein by reference. In this type of apparatus, a loop reaction conveyor is provided having an upper path, which is a forward path, and a lower, return path. The conveyor is substantially horizontally disposed. The conveyor comprises conveyor slats extending transversely for motion in a longitudinal direction. Each conveyor slat supports reaction containers. In the upper path, the slats move from a sample dispensing station at which aliquots of sample, generally human serum, are dispensed into selected reaction containers in a slat, which may also be referred to as a row. Corresponding reaction containers in adjacent slats define columns, and each column defines a channel for performance of a particular clinical chemistry. As a reaction container progresses in its column, reagents are added thereto from reagent dispensing means positioned over the loop conveyor. At the end of a row reacted contents are aspirated from the reaction container and analyzed, preferably spectrophotometrically.
Serum from one sample at a time is provided to sample dispensing means. The sample dispensing means then provides aliquots to the selected sample containers. During the next cycle, aliquots of a next serum sample must be delivered by the same dispensing means to a next row of reaction containers. It is very important that there be no carry over from one sample to the next in the dispensing means. This was successfully accomplished in the apparatus of the above-cited patents to Moran by moving the dispensing means to a sample table for aspiration of a sample and then moving the dispensing means to a dispensing station for dispensing to the sample cups. The sample had to travel through a conduit of minimum length, which conduit was washed after each delivery cycle to prevent carry over. This is to be distinguished from such systems as that disclosed in U.S. Pat. No. 3,799,744 issued Mar. 26, 1974 to Jones in which diluted samples travel through elongated conduits.
It is desirable to provide a reaction conveyor and sample supply system in which samples and their containers are conveniently and efficiently handled.